I don't see anything about CalDAV, sync or mobile integration on that site, though. The thing that actually makes Google/Nextcloud calendars useful is that they enable a workflow where you schedule events on your computer (where most scheduling happens, at least for me) and then are reminded of it on your phone (which is with you when/where scheduled events actually happen).

I'd go a step farther and say that in a business environment, trying to schedule a meeting and seeing when invitees are available is the killer feature for workplace environments.